9/11 sent New York scrambling to erect crude anti-automotive barriers, which architects recently replaced with more attractive LED-equipped sculptures on rotating turntables. Metropolis explains how the NYPD accepted the design after crashing a big truck into them. - Ed.

By 2002, the streets of the financial district in Lower Manhattan had become an urban designer's worst nightmare. Responding to calls for heightened security near the New York Stock Exchange — now a potential terrorist target — the city deployed a series of ugly half-measures that threatened to suck the life out of what was once one of the most active pedestrian thoroughfares in the country.

"First, there were those Jersey barriers," says Rob Rogers, a principal of Rogers Marvel Architects, the New York firm later hired to create security-based street improvements. "They were replaced by planters, which were just big gray boxes. Then the police department came in with giant orange urns, and later with pickup trucks filled with sand. Every week there was more stuff out there. Our project really started as an exercise in trying to get a master plan in place that would keep the proliferation of temporary stuff from proliferating further."

The project's first phase involved convincing the stakeholders-the myriad city departments and agencies, along with the New York Stock Exchange and the Alliance for Downtown New York-to replace the temporary solutions with sculptural bollards. "The idea was, if we got all of this crap off the street and swapped that mass with a minimum-sized object, we could open up the street," Rogers says. "Once we got buy-in from the police and fire departments and the counterterrorism guys, the question became, What will they look like?"

The faceted bollards-some anchored, others freestanding-were shaped by the requirements of the police department and contoured to shed water and serve as street furniture. Called "NoGos," they got their name from crash tests conducted by the Army Corps of Engineers, which labels successful trials "no-gos."

Phase two proved trickier. The city's planning department desperately wanted to replace the hideous steel grates, locked into the upright position, at seven controlled intersections in the district, where all vehicles are inspected before being allowed to pass. The challenge here was the complexity of subterranean Wall Street. "We tried to find a solution that would work but also be shallow enough to stay above the utilities and subway and fiber-optic cables," Rogers says.

The architect had seen an automated parking garage in Tokyo, which sparked the idea of a turntablelike device that would rotate a set of bollards into open and closed positions. The firm contacted companies that had worked on revolving restaurants and rail infrastructure. Eventually a full-scale mock-up was tested at the Texas Transportation Institute. "We brought the NYPD down and they crashed a big truck into it," Rogers says.

Though taller than the stationary NoGos, the turntable bollards share the same faceted aesthetic. Still, in early iterations the required extra height gave them a more imposing appearance than the architects wanted, so they began experimenting. The idea of perforating the surface to make them visually lighter led to the incorporation of LEDs, which glow red in the closed position and green in the open. Rogers says, "They're tough utilitarian things that we let become, if not objects of desire, then appreciable things in the streetscape."